Writing instrument



FIG. 1 is a perspective view showing my new design;

FIG. 2 is a front view of the writing instrument of FIG. 1;

FIG. 3 is a side view of the writing instrument of FIG. 1, the opposite side view being a mirror image thereof;

FIG. 4 is a rear view of the writing instrument of FIG. 1;

FIG. 5 is a top plan view of the writing instrument of FIG. 1; and,

FIG. 6 is a bottom plan view of the writing instrument of FIG. 1. 

The ornamental design for a writing instrument, as shown and described. 